9 Gallery Walls Done Right

I have a white, blank wall in my living room that needs major decorating love. I'd like to do a gallery wall once I have a good collection of art, so I decided to look for ones that I thought were successful.

The picks above are all different but suit the walls/rooms they occupy in terms of style and proportion. They each also feel balanced in their randomness or, in the case of the last one, in their uniformity. Take a look and share what you think. Have you tried to create a gallery wall and learned any tips/tricks?